Method for Modelling Geomechanical Pumped Storage in Horizontal Fluid-Filled Lenses
A method for modeling geomechanical subsurface pumped energy storage systems. In one embodiment, the method comprises applying a mechanical model developed for storage lens behavior during flowback (production), shut-in, and inflation (storage) stages. The model couples elastic deformation of the lens with Darcy-Weisbach fluid flow spanning the laminar to turbulent regimes, and includes an energy-based inlet boundary condition governing fluid flow rate out of the lens and up to the Earth's surface. The model also introduces pressure-dependent leakoff of fluid to the surrounding rock and the impact of intact rock bridges, which can arise from the lens having multiple petals or lobes, on lens compliance.
1 . A method of modeling flow performance of a subsurface fracture, comprising:
identifying a formation within which a fracture may be utilized for pumped energy storage and a fluid which may be pumped into or produced from the fracture via a wellbore;
obtaining one or more known characteristics of the formation, fracture, and fluid which impact flow performance of the formation;
assuming one or more unknown characteristics of the formation, fracture, and fluid which impact flow performance of the formation;
inputting the one or more known characteristics of the formation, fracture, and fluid and the one or more assumed characteristics of the formation, fracture, and fluid into a mechanical model of the formation; and
predicting flow performance of the fracture.
2 . The method of claim 1 , wherein the mechanical model comprises coupling elastic deformation aspects of the lens with Darcy-Weisbach fluid flow spanning the laminar to turbulent regimes.
3 . The method of claim 1 , wherein one or more of the known or assumed characteristics of the formation comprise a rock elasticity, a rock permeability, a near-wellbore tortuosity, or a near-wellbore perforation loss of the formation, or combinations thereof.
4 . The method of claim 1 , wherein one or more of the known or assumed characteristics of the fracture comprise a lens radius, or a fracture width of the fracture, or combinations thereof.
5 . The method of claim 1 , wherein one or more of the known or assumed characteristics of the fluid comprise a compressibility, or a density of the fluid, or combinations thereof.
6 . The method of claim 1 , further comprising inputting into the mechanical model one or more known or assumed characteristics of one or more surface components acting upon the fluid.
7 . The method of claim 6 , wherein at least one of the one or more surface components comprises a choke, a shut-in valve, or a turbine, or combinations thereof.
8 . The method of claim 1 , further comprising calibrating the model against a measured flow performance of a fracture.